When Jennifer Quinn springs into the air at Xtreme Trampolines, the 35-year-old feels like a kid again.

"It's a really fun place," she said of the Carol Stream warehouse, where the public can jump around on trampolines stitched together like a giant checkerboard. But the Chicago resident also remembers how she once "got crazy and nearly killed myself" by landing on her head. "I need to remember how old I am next time."

All the rage on the West Coast, trampoline parks are beginning to pop up in the Chicago area, with new parks proposed in Buffalo Grove, Naperville and Niles. Their owners say they offer a wholesome activity for all ages, adding that customers are briefed on safety and that padding minimizes the chance of injury.

But critics aren't convinced. Since the Carol Stream park opened in November, emergency call records show that 16 ambulances have been dispatched for trauma ranging from broken ankles and dislocated shoulders to a head injury.

In one instance, a 13-year-old girl fell on her neck and reported tingling in her arms and difficulty breathing.

The potential for devastating injuries concerns Dr. Gary Smith, director of the Center for Injury Research and Policy at Nationwide Children's Hospital in Columbus, Ohio. He sees the parks as a progression from the use of backyard trampolines, which nearly tripled the number of trampoline injuries in the 1990s, with 11 deaths, according to the U.S. Consumer Product Safety Commission.

The American Academy of Pediatrics, he noted, recommends against the use of trampolines other than in a supervised setting, such as in a gymnastics facility. It also warns against using trampolines as toys in the backyard and allowing children younger than 6 to participate.

A trampoline park "sounds like a very large backyard," he said. "That would not be where I would want my child to learn how to use the trampoline."

The controversy stirs the debate over where to draw the line between reasonable safety guidelines and freedom of choice.

Operators say no activity is risk-free. All customers, and guardians for those under 18, sign a waiver releasing Xtreme from liability if they are injured or killed.

Trampoline parks are safer than backyard trampolines, said Xtreme owner Eric Beck, because each trampoline is bordered by other trampolines or by a floor on the same level. He estimates his facility's injury rate at 2 in 1,000 customers.

"It's over 99 percent safe, not 100 percent safe," he said. "If you're not comfortable with the risk, don't do it."

After paying $11 for the first hour, Xtreme participants, whose average age is 16, are required to watch a three-minute video going over the rules. There are no shoes, running or roughhousing. There's also a limit of one person per trampoline, with no double-bouncing, in which one person lands to bounce another higher in the air. Participants are encouraged to stay within their abilities.

Still, injuries happen. Central DuPage Hospital in Winfield saw a noticeable increase in traumatic injuries after Xtreme opened, said Kristine Cieslak, medical director of the pediatric emergency room. She said the ER staff has treated numerous youths with broken legs and arms, and one with a fractured neck, fortunately without paralysis.

Parents and teens told her they didn't realize the risk.

Nationwide, almost 100,000 people go to emergency rooms each year for injuries due to trampoline accidents, including those in gymnasiums and at home, according to the product safety commission. Some other activities, like bicycling, basketball and football, have far more injuries, Beck points out. But the commission, which tracks those numbers, does not calculate the rate of injury per participant.

The pediatrics academy found relatively high rates of injury for some sports, including football and traditional gymnastics, but it did not address trampoline parks.

Unlike amusement parks, trampoline parks are not regulated in Illinois by any state or federal agency. That's because the parks do not involve a moving apparatus, according to the Illinois Department of Labor.

Instead, review of proposed trampoline parks falls to municipalities, but they don't typically get involved in operational safety issues.

For instance, officials in Naperville and Niles, where Sky High Sports plans to open trampoline parks in July, do not anticipate reviewing safety issues if the facilities meet all land-use requirements.

Carol Stream officials had the same approach when they approved the Xtreme facility, but Village Manager Joe Breinig said officials have become concerned about the injuries there.

Breinig said there's not much they can do, but they are trying to meet with the operators to ensure coordination with paramedics. Responders need to find victims immediately and in some cases extricate them from the foam pit, an area filled with foam cubes where people can practice flips over a softer surface. Firefighters sink into the foam and have a hard time getting patients out, he said.

"As with any other emerging enterprise, (trampoline parks) may fall through the cracks," Breinig said. "It's not something where you could do a minor tweak and change things."

Xtreme has run into resistance, though, in Buffalo Grove, where Beck wants to open a facility this summer.

After officials found out about the injuries in Carol Stream, the Plan Commission recommended against allowing Xtreme to open. The Village Board will consider the matter June 6, said Village President Jeff Braiman, and will consider safety, among other issues.

"It's a tough issue," said Plan Commission Chairman Eric Smith. "You could say, 'If you don't want your kid to go, you shouldn't let them go.' But we have to look out for the welfare of the community also. It sounded like a dangerous situation."

A leading critic is Mark Sohn, a former member of the U.S. gymnastics team who insures gymnastics facilities. He won't sell the coverage to trampoline parks because he said they don't have adequate training and supervision.

Most people, especially thrill-loving teens, have no idea of potential dangers, Sohn said.

By comparison, Sohn said, tumblers at a gymnastics club are taught individually and held, or "spotted," by a coach until they have developed each new skill.

"There's risk associated with everything, but this is a free-for-all," Sohn said. "In time, how many people are going to be quadriplegics or paraplegics?"

Jerry Raymond, co-owner of Sky High Sports, the other company expanding into the area, acknowledged the risks but said further regulation isn't needed. Moreover, he touts the health benefits of participating in the park's organized aerobic classes or dodge ball.

Raymond said he got out of computer consulting and into trampoline parks to start a more "family-friendly" venture for his teenage sons near San Francisco. By now, they have learned to do advanced flips, and they get more banged up bike riding and wrestling, he said.

"It is an extreme sport, like skateboarding or snowboarding," Raymond said. "There's going to be injuries. … I think we do a pretty fair job of watching out for that and keeping it under control."

On a recent afternoon at Xtreme, former Downers Grove South High School gymnast Jon Keslinke, 17, did flips off angled wall trampolines and landed with a grin on his face.

"I love it," he said. "It's everything that I want to do. You can experiment and do things you can't do outside."

He taught classmate Tracy Echert a back flip by holding the back of her shirt and helping her spin around, as coaches once taught him.

"It's scary," she said. "But it's fun."

Quinn, the adult trampoline jumper, agreed that teens, especially, should hear more blunt warnings about not trying flips they can't handle.